This invention relates to a heating or air-conditioning system for vehicles, particularly passenger cars, having a main heat exchanger consisting of a block of ribbed tubes against which the air flows that is guided into the passenger space and of a forward-flow radiator or tank through which the water flows and a return-flow radiator tank, as well as having one or several additional panel radiators that are connected to an additional circulating system and are arranged so that they are distributed at or in the inside of the interior of the vehicle.
Heating or air-conditioning systems of this type are known. In this case, the additional panel heat exchangers are, for example, arranged below the windshield or also under the seats and via an additional circulating system may be connected at the forward or inlet flow for the main heat exchanger. The disadvantage in the case of such systems is that the additional heating circulating system is fed with the hot forward-flow water so that special precautions must be taken to cause the additional panel heat exchangers to take on the temperature that is desired in each case. The arrangement of such additional heat exchangers is therefore relatively costly.
This invention is based on the objective of remedying this condition.
This invention is based on the recognition that, because of the lower temperatures of the heat exchange medium that are required as a rule, it is advantageous to admit to the additional heating circulating system the colder return flow of the main heat exchanger. With respect to details, the invention, in the case of a system of the initially mentioned type, consists of the fact that a forward-flow chamber for the additional circulating system is assigned to the return-flow radiator tank of the main heat exchanger. By means of this development, the supply of the additional heating circulating system can take place directly from the main heat exchanger without requiring additional separate control elements between the additional panel heat exchangers and their forward flow. In the case of air-conditioning systems, in which an evaporator is mounted in front of the main heat exchanger, said evaporator cooling the air that flows through the main heat exchanger and into the vehicle, the main heat exchanger, based on the development according to the invention, can serve as a cooling device for the fluid flowing through the additional circulating system so that in the cooling operation, the additional panel heat exchangers may also be utilized for the cooling of the interior of the vehicle which had not been possible previously.
Especially preferred embodiments include further advantageous features. Certain embodiments include different flow resistance tubes through the main heat exchanger block of ribbed tubes for the respective auxiliary and main heat exchanger circuit resulting in the advantage that a compact construction is possible for the heating or air-conditioning system despite the arrangement of an additional circulating system and therefore the previously customary construction of the main heat exchanger can be maintained. In certain preferred embodiments a separately controllable pump is provided in the auxiliary circulating system, a feature which makes possible a simple operation of the additional circulating system in the cooling operation, in which the heated cooling water does not flow through the main heat exchanger from the direction of the engine. In the case of a leakage in a component of the additional circulating system, the provision in certain embodiments of a blocking valve in the inlet to the auxiliary circulatory system which is controllable as a function of the water level in the main circulating system prevents that the cooling water level in the engine assumes a value that could endanger engine operation. The provision in certain embodimen of a one way valve in the auxiliary circuit return line ensures that the additional circulating system is not affected disadvantageously by the pressure conditions that may occur in the main heat exchanger.
Further objects, features, and advantages of the present invention will become more apparent from the following description when taken with the accompanying drawing(s) which show, for purposes of illustration only, an embodiment/several embodiments in accordance with the present invention.